Two of five abnormal protein bands in sera of febrile individuals appear to share antigenic determinants with the Amyloid A protein extracted from tissues of patients with chronic inflammatory disorders. This relationship will be further explored by paired electrophoretic and immunologic studies. The possibility that two further bands are antigenically related to immunoglobulin light chains will be tested by immune-absorption from purified fractions on anti-kappa and anti-lambda columns. Antigenic comparison between the most cathodal abnormal protein in serum and urine and a similar protein in CSF will be made using antiserum raised against the purified urinary protein. Tests for pyrogenicity of purified protein fractions from serum and urine will be made with the assistance of Dr. Phyllis Bodel of Yale University.